1. Richard C. Curtis Hematology Laboratory, Peter Bent Brigham Hospital, and the Department of Medicine, Harvard Medical School, Boston, Mass.
2. Harvard Medical School; Assistant in Medicine, Peter Bent Brigham Hospital, Boston, Mass.
3. Peter Bent Brigham Hospital; Research Associate, Harvard Medical School, Boston, Mass.
4. Harvard Medical School; Junior Associate, Peter Bent Brigham Hospital, Boston, Mass.
5. Peter Bent Brigham Hospital; Assistant Professor of Medicine, Harvard Medical School, Boston, Mass.